<?php

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * @package log4php
 */

/**
 * Converts ini configuration files to a PHP array.
 *
 * These used to be called "properties" files (inherited from log4j), and that
 * file extension is still supported.
 *
 * @package log4php
 * @subpackage configurators
 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version
 *          2.0
 * @version $Revision: 1343601 $
 * @since 2.2
 */
class LoggerConfigurationAdapterINI implements LoggerConfigurationAdapter
{

    /**
     * Name to assign to the root logger.
     */
    const ROOT_LOGGER_NAME = "root";

    /**
     * Prefix used for defining logger additivity.
     */
    const ADDITIVITY_PREFIX = "log4php.additivity.";

    /**
     * Prefix used for defining logger threshold.
     */
    const THRESHOLD_PREFIX = "log4php.threshold";

    /**
     * Prefix used for defining the root logger.
     */
    const ROOT_LOGGER_PREFIX = "log4php.rootLogger";

    /**
     * Prefix used for defining a logger.
     */
    const LOGGER_PREFIX = "log4php.logger.";

    /**
     * Prefix used for defining an appender.
     */
    const APPENDER_PREFIX = "log4php.appender.";

    /**
     * Prefix used for defining a renderer.
     */
    const RENDERER_PREFIX = "log4php.renderer.";

    /**
     * Holds the configuration.
     */
    private $config = array();

    /**
     * Loads and parses the INI configuration file.
     *
     * @param string $url
     *            Path to the config file.
     * @throws LoggerException
     */
    private function load($url)
    {
        if (! file_exists($url)) {
            throw new LoggerException("File [$url] does not exist.");
        }
        
        $properties = @parse_ini_file($url, true);
        if ($properties === false) {
            $error = error_get_last();
            throw new LoggerException("Error parsing configuration file: {$error['message']}");
        }
        
        return $properties;
    }

    /**
     * Converts the provided INI configuration file to a PHP array config.
     *
     * @param string $path
     *            Path to the config file.
     * @throws LoggerException If the file cannot be loaded or parsed.
     */
    public function convert($path)
    {
        // Load the configuration
        $properties = $this->load($path);
        
        // Parse threshold
        if (isset($properties[self::THRESHOLD_PREFIX])) {
            $this->config['threshold'] = $properties[self::THRESHOLD_PREFIX];
        }
        
        // Parse root logger
        if (isset($properties[self::ROOT_LOGGER_PREFIX])) {
            $this->parseLogger($properties[self::ROOT_LOGGER_PREFIX], self::ROOT_LOGGER_NAME);
        }
        
        $appenders = array();
        
        foreach ($properties as $key => $value) {
            // Parse loggers
            if ($this->beginsWith($key, self::LOGGER_PREFIX)) {
                $name = substr($key, strlen(self::LOGGER_PREFIX));
                $this->parseLogger($value, $name);
            }
            
            // Parse additivity
            if ($this->beginsWith($key, self::ADDITIVITY_PREFIX)) {
                $name = substr($key, strlen(self::ADDITIVITY_PREFIX));
                $this->config['loggers'][$name]['additivity'] = $value;
            }             

            // Parse appenders
            else 
                if ($this->beginsWith($key, self::APPENDER_PREFIX)) {
                    $this->parseAppender($key, $value);
                }                 

                // Parse renderers
                else 
                    if ($this->beginsWith($key, self::RENDERER_PREFIX)) {
                        $this->parseRenderer($key, $value);
                    }
        }
        
        return $this->config;
    }

    /**
     * Parses a logger definition.
     *
     * Loggers are defined in the following manner:
     * <pre>
     * log4php.logger.<name> = [<level>], [<appender-ref>, <appender-ref>, ...]
     * </pre>
     *
     * @param string $value
     *            The configuration value (level and appender-refs).
     * @param string $name
     *            Logger name.
     */
    private function parseLogger($value, $name)
    {
        // Value is divided by commas
        $parts = explode(',', $value);
        if (empty($value) || empty($parts)) {
            return;
        }
        
        // The first value is the logger level
        $level = array_shift($parts);
        
        // The remaining values are appender references
        $appenders = array();
        while ($appender = array_shift($parts)) {
            $appender = trim($appender);
            if (! empty($appender)) {
                $appenders[] = trim($appender);
            }
        }
        
        // Find the target configuration
        if ($name == self::ROOT_LOGGER_NAME) {
            $this->config['rootLogger']['level'] = trim($level);
            $this->config['rootLogger']['appenders'] = $appenders;
        } else {
            $this->config['loggers'][$name]['level'] = trim($level);
            $this->config['loggers'][$name]['appenders'] = $appenders;
        }
    }

    /**
     * Parses an configuration line pertaining to an appender.
     *
     * Parses the following patterns:
     *
     * Appender class:
     * <pre>
     * log4php.appender.<name> = <class>
     * </pre>
     *
     * Appender parameter:
     * <pre>
     * log4php.appender.<name>.<param> = <value>
     * </pre>
     *
     * Appender threshold:
     * <pre>
     * log4php.appender.<name>.threshold = <level>
     * </pre>
     *
     * Appender layout:
     * <pre>
     * log4php.appender.<name>.layout = <layoutClass>
     * </pre>
     *
     * Layout parameter:
     * <pre>
     * log4php.appender.<name>.layout.<param> = <value>
     * </pre>
     *
     * For example, a full appender config might look like:
     * <pre>
     * log4php.appender.myAppender = LoggerAppenderConsole
     * log4php.appender.myAppender.threshold = info
     * log4php.appender.myAppender.target = stdout
     * log4php.appender.myAppender.layout = LoggerLayoutPattern
     * log4php.appender.myAppender.layout.conversionPattern = "%d %c: %m%n"
     * </pre>
     *
     * After parsing all these options, the following configuration can be
     * found under $this->config['appenders']['myAppender']:
     * <pre>
     * array(
     * 'class' => LoggerAppenderConsole,
     * 'threshold' => info,
     * 'params' => array(
     * 'target' => 'stdout'
     * ),
     * 'layout' => array(
     * 'class' => 'LoggerAppenderConsole',
     * 'params' => array(
     * 'conversionPattern' => '%d %c: %m%n'
     * )
     * )
     * )
     * </pre>
     *
     * @param string $key            
     * @param string $value            
     */
    private function parseAppender($key, $value)
    {
        
        // Remove the appender prefix from key
        $subKey = substr($key, strlen(self::APPENDER_PREFIX));
        
        // Divide the string by dots
        $parts = explode('.', $subKey);
        $count = count($parts);
        
        // The first part is always the appender name
        $name = trim($parts[0]);
        
        // Only one part - this line defines the appender class
        if ($count == 1) {
            $this->config['appenders'][$name]['class'] = $value;
            return;
        }         

        // Two parts - either a parameter, a threshold or layout class
        else 
            if ($count == 2) {
                
                if ($parts[1] == 'layout') {
                    $this->config['appenders'][$name]['layout']['class'] = $value;
                    return;
                } else 
                    if ($parts[1] == 'threshold') {
                        $this->config['appenders'][$name]['threshold'] = $value;
                        return;
                    } else {
                        $this->config['appenders'][$name]['params'][$parts[1]] = $value;
                        return;
                    }
            }             

            // Three parts - this can only be a layout parameter
            else 
                if ($count == 3) {
                    if ($parts[1] == 'layout') {
                        $this->config['appenders'][$name]['layout']['params'][$parts[2]] = $value;
                        return;
                    }
                }
        
        trigger_error("log4php: Don't know how to parse the following line: \"$key = $value\". Skipping.");
    }

    /**
     * Parses a renderer definition.
     *
     * Renderers are defined as:
     * <pre>
     * log4php.renderer.<renderedClass> = <renderingClass>
     * </pre>
     *
     * @param string $key
     *            log4php.renderer.<renderedClass>
     * @param string $value
     *            <renderingClass>
     */
    private function parseRenderer($key, $value)
    {
        // Remove the appender prefix from key
        $renderedClass = substr($key, strlen(self::APPENDER_PREFIX));
        $renderingClass = $value;
        
        $this->config['renderers'][] = compact('renderedClass', 'renderingClass');
    }

    /**
     * Helper method.
     * Returns true if $str begins with $sub.
     */
    private function beginsWith($str, $sub)
    {
        return (strncmp($str, $sub, strlen($sub)) == 0);
    }
}

